//===================================================================================
// Microsoft patterns & practices
// Composite Application Guidance for Windows Presentation Foundation and Silverlight
//===================================================================================
// Copyright (c) Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===================================================================================
// The example companies, organizations, products, domain names,
// e-mail addresses, logos, people, places, and events depicted
// herein are fictitious.  No association with any real company,
// organization, product, domain name, email address, logo, person,
// places, or events is intended or should be inferred.
//===================================================================================
using System;
using System.Collections;
using System.Collections.Generic;

namespace Microsoft.Practices.Prism.Regions
{
	/// <summary>
	/// A collection of <see cref="IRegionBehavior"/> instances, that are stored and retrieved by Key.
	/// </summary>
	public class RegionBehaviorCollection : IRegionBehaviorCollection
	{
		private readonly IRegion region;
		private readonly Dictionary<string, IRegionBehavior> behaviors = new Dictionary<string, IRegionBehavior>();

		/// <summary>
		/// Initializes a new instance of the <see cref="RegionBehaviorCollection"/> class and associates it with a region.
		/// </summary>
		/// <param name="region">The region to associate the behavior collection with.</param>
		public RegionBehaviorCollection(IRegion region)
		{
			this.region = region;
		}

		/// <summary>
		/// Gets the <see cref="IRegionBehavior"/> with the specified key.
		/// </summary>
		/// <value>The RegionBehavior that's registered with the key.</value>
		public IRegionBehavior this[string key]
		{
			get { return this.behaviors[key]; }
		}

		/// <summary>
		/// Adds a <see cref="IRegionBehavior"/> to the collection, using the specified key as an indexer.
		/// </summary>
		/// <param name="key">The key that specifies the type of <see cref="IRegionBehavior"/> that's added.</param>
		/// <param name="regionBehavior">The <see cref="IRegionBehavior"/> to add.</param>
		/// <exception cref="ArgumentNullException">
		/// Thrown is the <paramref name="key"/> parameter is Null, 
		/// or if the <paramref name="regionBehavior"/> parameter is Null.
		/// </exception>
		/// <exception cref="ArgumentException">Thrown if a behavior with the specified Key parameter already exists.</exception>
		public void Add(string key, IRegionBehavior regionBehavior)
		{
			if (key == null)
				throw new ArgumentNullException("key");

			if (regionBehavior == null)
				throw new ArgumentNullException("regionBehavior");

			if (this.behaviors.ContainsKey(key))
				throw new ArgumentException("Could not add duplicate behavior with same key.", "key");

			this.behaviors.Add(key, regionBehavior);
			regionBehavior.Region = this.region;

			regionBehavior.Attach();
		}

		/// <summary>
		/// Checks if a <see cref="IRegionBehavior"/> with the specified key is already present.
		/// </summary>
		/// <param name="key">The key to use to find a particular <see cref="IRegionBehavior"/>.</param>
		/// <returns></returns>
		public bool ContainsKey(string key)
		{
			return this.behaviors.ContainsKey(key);
		}

		/// <summary>
		/// Returns an enumerator that iterates through the collection.
		/// </summary>
		/// <returns>
		/// A <see cref="T:System.Collections.Generic.IEnumerator`1"/> that can be used to iterate through the collection.
		/// </returns>
		public IEnumerator<KeyValuePair<string, IRegionBehavior>> GetEnumerator()
		{
			return behaviors.GetEnumerator();
		}

		/// <summary>
		/// Returns an enumerator that iterates through a collection.
		/// </summary>
		/// <returns>
		/// An <see cref="T:System.Collections.IEnumerator"/> object that can be used to iterate through the collection.
		/// </returns>
		IEnumerator IEnumerable.GetEnumerator()
		{
			return behaviors.GetEnumerator();
		}
	}
}